Pipe bender



Dec 8 F. HOTCHNER PIPE BENDER Filed March 8, 1922 INVENTOR. FR 0 HOTCHNER Patented Dec. 8,

, UNITED STATES PATIENT orrics.

v FRED HOTCHNER, OF SAN FRANCISCO, CALIFORNIA.

fl '0 all whom it may concern:

Be it known that I, From I-Io'roHNER, a citizen of the United States, residing at San Francisco, in the county of San Francisco, State of California, have invented a new and useful Pipe Bender, of which the following is a specification in such full and clear terms as will enable those skilled in the art to construct and use the same.

This invention relates to a tool for bending pipes, rods, bars or similar articles, and its object is to provide means whereby larger sizes of such articles can be bent than are ordinarily handled by tools of the general type of simple levers.

It will be understood by those skilled in the art that for bending inch, inch orone inch pipethat a tool is used which is similar to a screwed onto the end of a short piece of pipe for a handle. For bendng pipes larger than one inch it is necessary to use special power machines made for this purpose. These machines are not easily transported, and as large pipe or rod bending must be done in the field various expedients are resorted to, none of which are satisfactory and all of which are clumsy and expensive. This apparatus is constructed to be conveniently handled and carried to the work, and to enable the work to be done without the use of any other devices besides tl c tool itself.

Another object of the invention is to provide a bending apparatus which is capable of being operated manually with comparatively little effort because of the powerful leverages made use oi.

A further object ot this invention is to provide a pipe gripping jaw that will be adjustable both for various sizes of pipes and for the angle at which the tool holds 'onto the work.

It is a further object to provide a jaw that will apply pressure to the pipe in such a manner as not to flatten it.

Other objects of the invention will appear as the description proceeds.

An embodiment of the invention is shown in the accompanying drawings in which the same reference numeral is. applied to the Application filed March 8, 1922.

same portion throughout but I am aware that there may be modifications thereof.

Figure 1 is a side elevation of the bender set ready to begin the bending of a piece of pipe.

F ig. 2 is a side elevation of the bender after the pipe has been bent to nearly a right angle and the jaw has been reset to hold the tool at a diiierent angle to the work to secure a more convenient position for the mechanic to work in.

Fig. 3 is a side elevation of the bender folded for carryin F ig. 4 and Fig. 5 are respectively an elevation and a plan of the bender showing the details of construction.

Fig. 6 is a perspective View of the jaw.

Fig. 7 is an end view of a piece of pipe with the tool attachedto it, showing the manner in which the jaw bears on the pipe.

Numeral 1 indicates the bending arm one end of which is bent to form the grip 2 and the other end of which is drilled for the pin 4t which is set into it. Near the middle of arm 1 is the double otlset 3 which is for the purpose of permitting the jaw and grip to. fall in line with the quadrant and the handle, as shown in Fig. 5, and also to permit the handle to be folded back against the arm as shown in Fig. 3.

Around the arm 1 is the jaw 5 which is free to slide thereover. The jaw 5 is formed of the plates 6' and 7 joined by the plate 8 and the bar 9. The plate 8 is formed to a narrow edge at one end to fit into the teeth 10 on the arm 1.

The arm 1 is slightly greater in width at and secures a short hold on the pipe. This arrangement permits the tool to bend the smaller sizes of pipe in a shorter radius of bend while the general shape of the arm is Serial No. 541,934. 5

such as to secure the greatest strength for the material used since the arm is a cantilever when in use. On the pin 4; is the lever 13 which has the quadrant 14 at one end and the hole 15' at the other end, threaded to receive the pipe 16 which serves as a handle.

The quadrant 14 has the groove 17 in which fits a chain or cable 18.

The clutch 19 is formed of a bar bent into a U shape and is held on the lever 13 by means of the pin 20. The chain or cable is laid between the clutch and the edge of the lever. lVhen the strain is put on the tension member the clutch is caught by the links or strands and is pulled down thus pressing the tension member against the edge of the lever and holding it by friction. When the strain is released the chain is readily pulled back totake up the slack.

It will be seen from Fig. 1 that the entire tool forms a set of compound levers. The quadrant 14: ofthe lever 13 becomes the fulcrum of the first lever, being fixed in relation to the pipe 21 by the chain 18. The arm 1 becomes the second lever which has no definite fulcrum, but since the bending takes place at the points 11 and12 of the jaw 5, that point may be taken as the fulcrum and the grip 2 and pin 4, as the ends of the second lever. Since the whole forms a system that is changing in a number of difierent ways at once a true analysis would require a complicated mathematical formula. However an approximate comparison can be made between the power applied to the arm 1 as compared with the simple lever ordinarily used. The force applied at right angles to the handle multiplied by. the distance from the point at which the handle is held to the quadrant, divided by the distance from the quadrant to the pin 4 will give the force applied to the pin. The force applied to the pin multiplied by the distance from the pin to the grip and divided by the distance from the pin to the'grip plus the distance from the pin to the point at which the handle is held will give. the pressure which would have to be applied to asimple. lever to deliver the same bending force to the Work. This result divided by the force actually applied to the handle will give the mechanicaladvaiu tage of the tool.

When it is to be-used the tool is. set up as shown in Fig. 1. The grip 2 is slid under the pipe 21 and the arm is held at the desired angle to the work. The jaw is then adjusted to the pipe with the plate Shearin against one of the teeth on the arm 1;. One end oi; the chain. 18.. hasgbeen previous ly. wrapped around the pipe 21 and he d with a suitable hitch. The other end is. laid in the groove 17' ofthe quadrant land thru the; clutch 19. Bressure. then applied to When the tool is to be folded for trans-' portation the jaw 5 is slid back against the arm and the handle folded down against it as shown in Fig. 3.

As a pipe in bending tends to flatten out, it is necessary to provide some means for counteracting this tendency. Previously, in bending pipe'it has been customary to confine the pipe againstlateral movementby side flanges on the bending means. This is. not always satisfactory as there is necessarily some chance for the pipe to start bending flat, and once it starts to flatten it is liable to collapse in spite of means designed to prevent it. In this invention means are pro vided to force the walls together with a definite pressure which will be in proportion to the amount of pressure tending to bend the pipe in an arc. Collapsing is thus prevented, not by confining the pipe against lateral movement but by preventing the lateral movement from starting. As shown in Fig. 7 the ends Hand 12 of the plates 6 and 7 of the jaw 5, bear on the sides of the pipc thus tending to force the sides together.

lVhat I claim is as follows, but various modifications may be made in the construction shown in the drawings and above particularly described form, within the purview of my invention.

1. A pipe bender comprising a lever having a pipe embracing hook, a fulcrum on said lever, a second lever pivotally mounted on the first lever at the end distant from said pipe embracing hook, and means we tending from the short arm of the second lever, for engaging a pipe at a distance from said hook, whereby on the application of power to the second lover a pipe may be bent.

2. A pipe bender comprising a lever having a pipe embracing hook at one end, a movable fulcrum on said lever, a second lever pivotally mounted on the first lever, means to connect the short armthereof to a pipe, and means to hold the said connecting means engaged with the second lever, whereby on moving the second lever a pipe may be bent.

3'. In apipe bender, a-leverhavingaseries of notches and a. pipe embracing.- hook, a movable fulcrumon said lever, adapted: to engage any of the notches, a second lever pivotally mounted oaths first lever, a chain for engaging the pipe, and means to hold the to connect the short arm of thesecond lever chain engaged with the second lever, Whereto the pipe at a point on the opposite side of by pressure may be applied to the pipe to the fulcrum from the hook. 10

bend it by drawing the second lever. In testimony whereof I have hereunto set 5 4:. A lever having a pipe engaging hook, my hand this 27th day of February A. D.

an adjustable fulcrum thereon, a second 1922.

lever pivoted on the first lever, and a chain FRED HOTGHNER. 

